The airline, which is owned by Sir Richard Branson, opened an urgent investigation on Thursday night after the woman allegedly passed on information about eight celebrities to the Big Pictures agency.

The stars understood to be targeted include Hollywood actors Scarlett Johansson, Gwyneth Paltrow and Sienna Miller and singers Robbie Williams and Nicole Scherzinger.

Other high profile names whose flight details were accessed include Ashley Cole, the Chelsea and England footballer, his former wife and singer Cheryl Cole and Jermain Defoe, the Tottenham footballer.

The employee, reported to be a supervisor of Upper Class customers, quit after her alleged deal with the organisation was publicly exposed.

The airline was last night attempting to contact the celebrities and sources said an investigation had been launched to establish who could access its booking system. Officials were also urgently trawling the company’s email archives.